Devices for recovering of oil and gas from long, horizontal and vertical wells are known from U.S. Pat. Nos. 4,821,801, 4,858,691, 4,577,691 and GB patent publication No. 2169018. These known devices comprise a perforated drainage pipe with, for example, a filter for control of sand around the pipe. A considerable disadvantage with the known devices for oil/and or gas production in highly permeable geological formations is that the pressure in the drainage pipe increases exponentially in the upstream direction as a result of the flow friction in the pipe. Because the differential pressure between the reservoir and the drainage pipe will decrease upstream as a result, the quantity of oil and/or gas flowing from the reservoir into the drainage pipe will decrease correspondingly. The total oil and/or gas produced by this means will therefore be low. With thin oil zones and highly permeable geological formations, there is also a high risk of coning, i.e. flow of unwanted water or gas into the drainage pipe downstream, where the velocity of the oil flow from the reservoir to the pipe is the greatest.
From World Oil, vol. 212, N. 11 (11/91), pages 73-80, it is known to divide a drainage pipe into sections with one or more inflow restriction devices such as sliding sleeves or throttling devices. However, this reference mainly deals with the use of inflow control to limit the inflow rate for up hole zones and thereby avoid or reduce coning of water and or gas.
WO-A-9208875 describes a horizontal production pipe comprising a plurality of production sections connected by mixing chambers having a larger internal diameter than the production sections. The production sections comprise an external slotted liner which can be considered as performing a filtering action. However, the sequence of sections of different diameter creates flow turbulence and prevents the running of work-over tools operated along the outer surface of the production pipe.
When extracting oil and or gas from geological production formations, fluids of different qualities, i.e. oil, gas, water (and sand) is produced in different amounts and mixtures depending on the property or quality of the formation. None of the above-mentioned known devices are able to distinguish between and control the inflow of oil, gas or water on the basis of their relative composition and/or quality.
Devices as disclosed in WO2009/088292 and WO 2008/004875 are robust, can withstand large forces and high temperatures, can prevent draw downs (differential pressure), need no energy supply, can withstand sand production, yet are reliable, simple and very cheap. However, several improvements might nevertheless be made to increase the performance and longevity of the above device in which many of the different embodiments of WO2009/088292 and WO 2008/004875 describe a disc or plate as a movable body of the valve.
One potential problem with a disc or plate as the movable body is erosion on the movable body. This is due to a very large fluid velocity between an inner seat and the movable body of the valve. The fluid is subjected to abrupt changes in its flow direction at this location. As there will always be particles in the fluid flow, even if sand screens are installed, such particles will cause erosion. The erosion problem exists both with and without the use of a stagnation chamber in the valve.